Knowing how to measure pants size is important to ensure a proper fit when purchasing pants. The most important measurements are the waist size, inseam, and leg opening. The waist size is the circumference of the waist, measured in inches. The inseam is the length from the crotch to the hem, measured in inches. The leg opening is the circumference of the leg opening, measured in inches.
To measure the waist size, use a measuring tape to measure around the natural waistline. To measure the inseam, use a measuring tape to measure from the crotch to the desired hem length. To measure the leg opening, use a measuring tape to measure around the leg opening, just below the knee.